A GRID GENERATION TECHNIQUE FOR NUMERICAL MODELLING HEAT and MOISTURE MOVEMENT IN PEAKED BULKS of GRAIN

This paper describes a numerical solution procedure to study heat and moisture transfer processes by two-dimensional natural convection phenomena in grain stores with arbitrary geometries. This enables grain storage technologists to investigate the design and performance of grain stores in which the grain surface is peaked, as in bunker storage, for example. Momentum transfer is described by an elliptic partial differential equation, which governs the behavior of the stream function. Using an algebraic grid generation technique, the governing equations are transformed into a body-fitted rectangular coordinate system that allows coincidence of all boundary lines with a coordinate line. Numerical solutions of the resulting equations are obtained using an alternating direction implicit method. Results from numerical experiments on a peaked bulk of stored grain retained between two vertical walls are obtained that show the magnitude and directions of convection currents and contours of temperature, moisture, dry matter loss and chemical pesticide concentrations.